The role of infection and immunity in atherosclerosis

Cardiovascular diseases account for 20% of deaths worldwide, rising to 50% in developed countries. Current understanding of atherosclerosis derives from a combination of research in animals and cell cultures, analysis of human lesions, clinical investigations of patients with acute coronary syndromes and epidemiological studies of coronary artery disease. By measuring serologic titers in the serum of patients after cardiovascular events, it was observed that the greater the infectious exposure of a patient, the larger the atherosclerotic lesion extension. In addition, gene targeting or pharmacological inhibition of certain cytokines aggravates atherosclerosis in animal experiments. Other animal experiments have succeeded in proving that B cells play a protective role in atherosclerosis through induced immunity against oxidized low-density lipoprotein and other epitopes. Molecular mimicry might respond to the question of how infection may trigger vulnerability in previously stable atherosclerotic lesions. The FLU Vaccination Acute Coronary Syndromes trial enhanced the debate on atherosclerosis prevention by the application of antiflu vaccine. So far, antibiotics have failed to reduce cardiovascular risk, as recent trials could not demonstrate a statistically significant risk reduction. Having assumed atherosclerosis to be an inflammatory disease, the WHO considered the possible role of secondary prevention with antiflu vaccine.